a) Field of the Invention
This invention relates to a resin composition for an electrophotographic toner useful in developing latent electrostatic images in electrophotography, electrostatic recording, electrostatic printing or the like and also to an electrophotographic toner comprising the resin composition.
b) Description of the Related Art
A toner for use in a copying machine or a printer is required to have sufficient "charging rise property", that is, a property that the quantity of electricity charged on the toner instantaneously increases to an appropriate value in response to a start-up of a machine such as a copying machine or a printer. It has heretofore been the practice to add a metal-containing dye called a "charge control agent (CCA)", such as a metal salicylate, to a toner so that the toner can be provided with improved chargeability. However, attempts have recently been made with a view to providing a toner resin itself with the function of CCA for the reduction of the amount of CCA or for the total elimination of CCA, because CCA contains a heavy metal, has high toxicity in many instances and is expensive.
Examples which are each directed to the use of a polymer containing a maleic acid derivative are disclosed, for example, in Japanese Patent Publication No. 88472/1993. This approach however involves problems such that toner particles cannot be charged evenly, fogging tends to occur and the developing performance is poor.